Highest mortality rate of all viral haemorrhagic fevers (25-90%)
The first recognized Ebola outbreak occurred in 1976, near the Ebola River in Zaire (now Democratic Republic of Congo, DRC). Over the past 40 years, more than 20 outbreaks have occurred in Africa, with most of the known outbreaks occurring in the past 20 years. Before the 2014 epidemic, over 2300 cases with greater than 1500 deaths had been documented from this disease. The current outbreak in West Africa has so far affected more people than all previous Ebola outbreaks combined: as of January 20, 2015, the cumulative number of probable, suspect and laboratory-confirmed cases attributed to Ebola virus was more than 21,000, with greater than 8500 deaths. These numbers likely represent underestimates of the outbreak’s true size because of poor local health system infrastructure, with many patients being cared for outside hospital settings, or not reported.
EVD outbreaks typically start from a single case of probable zoonotic transmission, followed by human-to-human transmission via direct contact or contact with infected bodily fluids or contaminated fomites.
Animal-to-human transmission: Occurs through handling bush meat or direct contact with infected nonhuman primates (such as chimpanzees, gorillas, fruit bats, and monkeys).
Human-to-human transmission: Direct contact via blood and body fluids (including but not limited to urine, feces, vomitus, saliva and sweat) through breaks in the skin or through inoculation into the mouth, nose or eyes.
To date, 12 distinct filoviruses have been described. Ebolaviruses are negative stranded RNA viruses that belong to the Filoviridae family and are endemic to regions of west and equatorial Africa.
Ebola virus (EBOV):
Ebolaviruses belong to the genus Ebolavirus of the family Filoviridae in the order Mononegavirales, viruses whose genome consists of a single strand of RNA with negative polarity
Characterized by fever, gastrointestinal signs and multiple organ dysfunction syndrome. The incubation period is typically 8–10 days (range, 2–21 days, though it may be shorter when transmission has occurred through contaminated injection needles).
Abrupt onset of fever, chills, malaise, anorexia, severe headache and myalgias of the trunk and lower back
Diffuse maculopapular rash by days 5–7 of illness, mainly on the trunk.
Occur several days after the initial nonspecific presentation and become the predominant clinical feature
Vomiting, nausea, watery diarrhea and abdominal pain
Bleeding disorders (< 50% cases):
Petechia, bruising, oozing from venipuncture sites and/or mucosal hemorrhage
Conjunctival injection and dark red discoloration of the soft palate are common physical findings
Central nervous system involvement:
Somnolence, delirium, seizures or coma.
EBOV can be transmitted transplacentally and also lead to fetal death related to placental insufficiency. EBOV RNA has been detected at high concentrations in amniotic fluid, placenta, fetal tissue and breast milk
Newborn rarely survive
Higher risk for severe illness and death
In nonfatal cases, patients improve typically 6–11 days from onset of symptoms. Fatal disease is associated with more severe clinical signs early in infection
Progression to: Disseminated intravascular coagulation (DIC), septic shock, multiorgan failure
Death usually occurs between 6 and 16 days (mostly around the 9th day) after symptom onset.
Diagnosis requires a combination of case definition and laboratory tests, typically real-time reverse transcription PCR to detect viral RNA or rapid diagnostic tests based on immunoassays to detect EBOV antigens.
Reverse transcriptase polymerase chain reaction (RT-PCR): Detects viral RNA in blood samples of infected patients immediately after commencement of signs and symptoms
Enzyme-linked immunosorbent assay (ELISA): Detects IgG & IgM in samples of infected patients
Initial nonspecific symptoms can be mistaken for other,
Other infections with exanthems: Measles or meningococcemia
Till date, there is no precise antiviral management or vaccination for EVD. Management protocol mainly relies on supportive and symptomatic therapy. Public health strategies emphasizing on epidemiological surveillance, contact tracing, and quarantine of the patient have been recommended to combat the dissemination of EVD.
IV fluids and oral rehydration solution: Electrolyte substitute and maintain the intravascular volume
Antiemetics and antidiarrheal drugs (for unrelenting vomiting and diarrhea)
Prophylactic antibiotics (third generation IV cephalosporins (secondary bacterial infections and septicemia)